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Question re: Patterns for Turning

If you have a pattern for turning printed full size on paper similar to the one on the right, would you want dimensions on it? If so, what dimensions? Would you want just an overall length to check the printing with? Would you want diameters at certain points along the leg? Thanks for your time.

Re: Question re: Patterns for Turning

Originally Posted by Dave Richards

If you have a pattern for turning printed full size on paper similar to the one on the right, would you want dimensions on it? If so, what dimensions? Would you want just an overall length to check the printing with? Would you want diameters at certain points along the leg? Thanks for your time.

If you can supply a full size drawing (half section) like you have, no dimensions are needed as long as a person can print it full size. There in lies the issue usually, being able to print full size, a 32" printer possibly. All a turner needs are the transition lines (along the center axis) and the diameters at those points to work to, as well as minimum diameters they all can be scaled from a full size drawing. So, to answer your question, maybe datum dimension all the transition points from one end and give diameters at all of those points as an alternative to no dimensions.

Re: Question re: Patterns for Turning

Dave, this looks like a table leg, so I would think you would need a dimension of the major diameters so you could scale them up or down. A farmhouse type table would need larger legs than a coffee table. It looks like the outside of the curves all line up as do the lowest part of the coves.

Re: Question re: Patterns for Turning

Supplying the drawing at full size in PDF form is no problem and the PDF could easily be printed by an office supply house. Index marks could be added to the sheet for post printing from Adobe Acrobat or Reader.

Roy, it [i]is[/is] a farmhouse style table leg. In this case the top is 5 in. square.

A grid could be added easily as well.

FWIW, I used the 2D DXF file from Osborne Wood Products to make this example drawing just to save a bit of time. I'm thinking more of custom patterns or perhaps creating patterns by lifting dimensions off of existing antiques and such.

Re: Question re: Patterns for Turning

In general, turnings are designed to minimize the need for too much measuring. In your example it looks like all the crests of the beads and balls (large beads) are at the same diameter as the square once it has had the corners removed - just turn till the flats are gone and smooth up with a chisel taking as small a shaving as possible. All the fillets or shoulders appear to be the same diameter (except for the one at the top, which is the same diameter as the rounded blank), so you would measure all these (fillets) with a caliper and parting tool as soon as you have rounded the leg (minus the square left at the top). You make these cuts at the appropriate places, leaving the space for the bead or ball full size and use the parting tool to make a straight line between the shoulders where there will be coves. Then the beads and balls are just gentle curves that connect the outside diameter to the shoulder and the coves are gentle curves connecting the shoulder to a point in the middle that looks right to you - you don't measure the depth of coves, you measure the width and judge the depth by what looks right. So all of this is done with only one set of calipers. Finally you have the foot. You could either set a second set of calipers for this diameter or just turn it by eye.

Remember that in turning the only part that needs to be turned to a precise dimension is a tenon (of which you have none here) because it has to fit tightly into a mortise, all the rest just has to look right. No one will measure these parts with a machinist's caliper and tell you that one cove is a few thousandths (or even a sixteenth or an eighth) different than the next. And these pieces will be separated from each other by the width and length of the table, so direct comparison is difficult. After turning the first piece, if you are satisfied with the way it looks, you can use that to hold beside the next ones as you get close to finishing them. That will be the closest comparison any one will ever be able to make. You are probably your own harshest critic.

Re: Question re: Patterns for Turning

Thanks Jim. I'm not planning to turn legs from the patterns I'd be making. I had a request from someone who wondered if I could make full size patterns for them. Frankly, if I was turning legs from a pattern like this, I'd not be too concerned about exact dimensions but I just wondered what others who do a lot of turning would want. I'd be happy with lifting dimensions off the drawing after checking a couple of basic ones to see that the print was correct.

Re: Question re: Patterns for Turning

Timely question, Dave. I just drew plans for a dining table w/ a leg very similar to the one you show. Here are pics of the dimensions I added to my working drawings for upper and lower legs. Granted, I'm a little OCD, but I like to have all the details worked out before I start a project.

Re: Question re: Patterns for Turning

Originally Posted by Bill Clemmons

Timely question, Dave. I just drew plans for a dining table w/ a leg very similar to the one you show. Here are pics of the dimensions I added to my working drawings for upper and lower legs. Granted, I'm a little OCD, but I like to have all the details worked out before I start a project.

Was that drawing created from that model?. Im OCD too and wonder where the radius near the top fell off the model. from the top you have a 1/4wide flat dia, a cove, another flat and then a radius... that radius isnt in the model

Re: Question re: Patterns for Turning

Originally Posted by chris_goris

Was that drawing created from that model?. Im OCD too and wonder where the radius near the top fell off the model. from the top you have a 1/4wide flat dia, a cove, another flat and then a radius... that radius isnt in the model

Chris, in SketchUp when I create a round column I start w/ a flat, 2D drawing of half the profile, then use "follow me" to fill out the column. If you're not familiar w/ creating a column in SU, this may sound confusing. Dave can probably explain it better than I did.

For the dimensions, I take that flat, half profile and turn it into a full profile. I then apply my dimensions to that. To turn the half profile into a full profile, copy and move the half the distance of your overall diameter, then flip it along the axes (in my case, the red axis). Again, Dave can probably explain this better.

As for that undimensioned radius, that is a transition from one known dimension (3d) to another (2d). Once I have the two diameters established, it is a simple matter to freehand that radius. Actually, all the dimensions on the left side are diameters. SU will actually give you the radius, but once I get to that point, I go w/ whatever is visually pleasing to the eye.

Originally Posted by Dave Richards

Out of curiosity, will you be leave the transition from square to round sharp as you show it in your model?

Good catch, Dave. No, I'll fade the transition up about 3/8 - 1/2". I just didn't know how to show that in SketchUp.

Last edited by Bill Clemmons; 03-13-2018 at 08:58 PM.

I'll gladly tell you how I do something. Just please don't confuse that with the right way to do it, and almost certainly not the only way.